1. Field of the Invention
This invention relates to construction of dual-crystal accelerometers having a liquid inertial mass. A method is provided for balancing certain electrical characteristics between the two crystals.
2. Discussion of the Prior Art
Accelerometers employing dual piezo-electric wafers having a liquid inertia mass contained in a chamber between the two crystals have been disclosed in U.S. Pat. No. 4,334,296, issued June 8, 1982 in the name of E. M. Hall, Jr. and assigned to the assignee of this invention.
One of the problems associated with that type of accelerometer is the problem of matching the capacitance and the sensitivity of the two piezo-electric wafers so that the electrical output signals of the two wafers will be comparable. A means for sensitivity-matching was disclosed in U.S. Pat. No. 4,395,908, issued Aug. 8, 1983 to R. C. Shopland, also assigned to the assignee of this invenion. In that patent, a threaded end cap is provided that may be rotated to apply a greater or lesser tension to one of the wafers to match its sensitivity to that of the second of the two wafers. But that method affected only sensitivity, not capacitance.
It is therefore an object of our invention to provide a method for matching both the sensitivity and the capacitance of the two piezo-electric wafers of a dual-crystal accelerometer.